A spring and wooded habitat at FLK Zinj and their relevance to origins of human behavior

Abstract

International audienceThe 1959 discovery of the hominin fossil Zinjanthropus boisei brought the world's attention to the rich records at Olduvai Gorge, Tanzania. Subsequent excavations of archaeological level 22 (FLK Zinj) Bed I uncovered remains of Homo habilis and a high-density collection of fossils and Oldowan stone tools. The occurrence of this unusual collection of bones and tools at this specific location has been controversial for decades. We present paleoecological data that provide new insights into the origin of FLK Zinj. Our recent excavations 200 m north of the site uncovered a 0.5-m-thick tufa mound draped by Tuff IC, in the same stratigraphic horizon as level 22. Stable isotope analyses indicate that the carbonates were deposited by a freshwater spring. Phytolith analysis of the waxy clay under Tuff IC revealed abundant woody dicotyledon and palm phytoliths, indicating that the site was wooded to densely wooded. The time equivalency and close physical proximity of the two environments indicate the two are related. This study has provided the first documented evidence of springs in Bed land these data have important implications for the interpretation of hominin behavior in meat acquisition and the ongoing debate on scavenging versus hunting

Archaeology of middle Pleistocene lacustrine and spring paleoenvironments in the Kapthurin Formation, Kenya

“…In such arid environments standing bodies of fresh water are rare, and are usually fed by underground aquifers. In such a setting, fresh water springs, if they are present, provide not only a valuable source of drinking water, but also serve as a focal point for the exploitation of locally plentiful plant and animal resources (Caton- Thompson, 1952;Sept, 1986;Deacon, 1989;Haynes et al, 1997;Nicoll et al, 1999;Smith et al, 2004;Garcea and Giraudi, 2006;Ashley et al, 2009Ashley et al, , 2010a. During times of increased rainfall, underground aquifers can be recharged, allowing springs to continue flowing even after the cessation of local precipitation (Smith et al, 2007), thus increasing the potential of arid environments to continue to support a more diverse plant and animal community.…”

“…A better understanding of the resources afforded by a large standing body of fresh water has forced a revision of previous interpretations of archaeological materials previously thought to have accumulated in rather inhospitable environments (Ashley et al, , 2010a. Evidence from Olduvai Gorge and from oases in the Sahara has highlighted the importance of fresh water springs to the support of diverse faunal and plant communities in arid environments (Ashley et al, , 2010a(Ashley et al, , 2010bHaynes et al, 1997;Nicoll et al, 1999;Smith et al, 2004;Garcea and Giraudi, 2006).…”

“…Evidence from Olduvai Gorge and from oases in the Sahara has highlighted the importance of fresh water springs to the support of diverse faunal and plant communities in arid environments (Ashley et al, , 2010a(Ashley et al, , 2010bHaynes et al, 1997;Nicoll et al, 1999;Smith et al, 2004;Garcea and Giraudi, 2006). These would have been focal points for hominin subsistence activities.…”

“…The best documented correlation between early Pleistocene hominin occupation and fresh water springs in East Africa occurs in Bed I at Olduvai Gorge (Ashley et al, , 2010a. Here hominins consistently exploited fresh water wetlands and springs especially during dry periods .…”

“…In semi-arid environments, standing bodies of fresh water are rare, and represent not only a source of potable water but also a productive locale rich in plant and animal resources (Sept, 1986;Rogers et al, 1994;Johnson et al, 2009;Ashley et al, 2009Ashley et al, , 2010a. In the hyper-arid regions of North Africa, there is a demonstrated link between periods of increased available surface water, often in the form of fresh water springs, and increased intensity of human occupation (Caton- Thompson, 1952;Haynes et al, 1997;Nicoll et al, 1999;Smith et al, 2004;Garcea and Giraudi, 2006).…”